Show or hide HTML code based on URL - php

Question

I am working on a form and I've stumbled upon a problem. I have different users in which I want them to see different values for one of my SELECT tags; so far I am using PHP to get the URL and if $field == 'donor' then it takes off some of the options. Here's the code:
function defineUser($field){
if(isset($_GET['user']) && urldecode($_GET['user'])){
$field = urldecode($_GET['user']);
if($field == "donor"){
return "<p>
<label for=designation>Designation</label>
<select name='merchant_defined_field_4' id='merchant_defined_field_4' required=''>
<option value=''>Select...</option>
<option value=''>Option 1</option>
<option value=''>Option 2</option>
<option value=''>Option 3</option>
<option value='Other'>Option 4</option>
</select>
</p>";
} else if ($field != "donor") {
return "<p>
<label for=designation>Designation</label>
<select name='merchant_defined_field_4' id='merchant_defined_field_4' required=''>
<option value=''>...</option>
</select>
</p>";
} else {
return "<p>
<label for=designation>Designation</label>
<select name='merchant_defined_field_4' id='merchant_defined_field_4' required=''>
<option value=''>...</option>
</select>
</p>";
}
}
}
This is my function, now on the page source itself I simply have,
<?php echo defineUser($_GET['user']); ?>
My question simply is how can I get each user to see a standard options set - inside my select tag - based on the URL the user has been sent from?

Answer 1

Your code could be simplified:
function defineUser() {
$user = isset($_GET['user']) ? urldecode($_GET['user']) : null;
switch ($user) {
case 'donor':
return "<p>
<label for=designation>Designation</label>
<select name='merchant_defined_field_4' id='merchant_defined_field_4' required=''>
<option value=''>Select...</option>
<option value=''>Option 1</option>
<option value=''>Option 2</option>
<option value=''>Option 3</option>
<option value='Other'>Option 4</option>
</select>
</p>";
break;
default:
return "<p>
<label for=designation>Designation</label>
<select name='merchant_defined_field_4' id='merchant_defined_field_4' required=''>
<option value=''>...</option>
</select>
</p>";
}
}
You don't need to pass it $_GET['user'] since that is globally accessible, unless you're worried about dependency. Second, you were essentially repeating the same block of HTML twice in your if else clause, using a switch here makes more sense.